Wireless communication apparatus, wireless communication system, and wireless communication method

Abstract

A wireless communication apparatus includes a plurality of antennas, and a controller configured to cause a multicast frame including distribution data and a return request to be transmitted from the antennas, and the multicast frame to be re-transmitted when the antennas receive one or more return frames as a response to the multicast frame and an intensity of the return frames meets a predetermined condition.

What is claimed is: 
     
       1. A wireless communication device, comprising:
 a plurality of antennas; and 
 a controller configured to
 cause a multicast frame including distribution data and a return request to be transmitted from the antennas, and the multicast frame to be re-transmitted when the antennas receive return frames as a response to the multicast frame and an intensity of the return frames meets a predetermined condition, and 
 cause a unicast frame including the distribution data, the return request and an address of a single target receiving device, to be transmitted to the single target receiving device, when the antennas receive the return frames and the intensity of the return frames does not meet the predetermined condition. 
 
 
     
     
       2. The wireless communication device according to  claim 1 , wherein
 the return request causes a receiving device to transmit the return frame when the receiving device fails to demodulate the distribution data in the multicast frame. 
 
     
     
       3. The wireless communication device according to  claim 1 , wherein
 the predetermined condition is met when the intensity of the return frames is greater than a predetermined level. 
 
     
     
       4. The wireless communication device according to  claim 3 , wherein
 the controller is configured to measure the intensity of the return frames after a predetermined period of time from the transmission of the multicast frame. 
 
     
     
       5. The wireless communication device according to  claim 1 , wherein
 the multicast frame includes an address of each of a plurality of target receiving devices. 
 
     
     
       6. The wireless communication device according to  claim 1 , wherein
 the target receiving devices are all receiving devices within a wireless communication network established with the wireless communication device. 
 
     
     
       7. The wireless communication device according to  claim 1 , wherein the controller is further configured to cause the unicast frame to be transmitted from one of the antennas. 
     
     
       8. The wireless communication device according to  claim 1 , wherein
 when the intensity of the return frames meets the predetermined condition, the controller causes a plurality of unicast frames to be transmitted sequentially to each of receiving devices that returned a negative acknowledgement within the return frame. 
 
     
     
       9. A wireless communication system, comprising:
 a wireless communication device that transmits a multicast frame and a unicast frame; and 
 a plurality of wireless communication receiving devices, wherein 
 the wireless communication device includes:
 a plurality of antennas; and 
 a controller configured to
 cause the multicast frame, which includes distribution data and a return request, to be transmitted from the antennas, and the multicast frame to be re-transmitted when the antennas receive return frames from the wireless communication receiving devices as a response to the multicast frame and an intensity of the return frames meets a predetermined condition, and 
 cause the unicast frame including the distribution data, the return request and an address of a single target receiving device, to be transmitted to the single target receiving device, when the antennas receive the return frames and the intensity of the return frames does not meet the predetermined condition. 
 
 
 
     
     
       10. The wireless communication system according to  claim 9 , wherein
 the return request causes each of the wireless communication receiving devices to transmit the return frame when said each of the wireless communication receiving devices fails to demodulate the distribution data in the multicast frame. 
 
     
     
       11. The wireless communication system according to  claim 9 , wherein
 the predetermined condition is met when the intensity of the return frames is greater than a predetermined level. 
 
     
     
       12. The wireless communication system according to  claim 9 , wherein
 the controller is configured to measure the intensity of the return frames after a predetermined period of time from the transmission of the multicast frame. 
 
     
     
       13. The wireless communication system according to  claim 9 , wherein
 the multicast frame includes an address of each of a plurality of target wireless communication receiving devices. 
 
     
     
       14. The wireless communication system according to  claim 9 , wherein
 the target receiving devices are all of the wireless communication receiving devices of the wireless communication system. 
 
     
     
       15. The wireless communication system according to  claim 9 , wherein the controller is further configured to cause the unicast frame including the distribution data and the return request to be transmitted from one of the antennas. 
     
     
       16. The wireless communication system according to  claim 15 , wherein
 when the intensity of the return frames meets the predetermined condition, the controller causes a plurality of unicast frames to be transmitted sequentially to each of receiving devices that returned a negative acknowledgement within the return frame. 
 
     
     
       17. A method for wirelessly distributing data from a wireless communication device to a plurality of receiving devices, comprising:
 transmitting a multicast frame including distribution data and a return request to the plurality of receiving devices; 
 when a predetermined amount of time has elapsed from the transmission of the multicast frame, determining an intensity of one or more return frames received from the receiving devices as a response to the multicast frame; 
 when the intensity of the return frames meets a predetermined condition, re-transmitting the multicast frame to the plurality of receiving devices; and 
 when the intensity of the return frames does not meet the predetermined condition, transmitting a unicast frame including the distribution data, the return request and an address of a single target receiving device to each of one or more receiving devices that returned a negative acknowledgement within the return frame.